Baby not sleeping through the night
The trick question at every family gathering. Here is what the phrase actually means, and when it starts to make sense.
It is the question everyone asks new parents, often with a smile, sometimes before you have left the hospital: “so, are they sleeping through?”
It is a trap, because nobody means the same thing by it.
What the phrase means
In infant sleep research, “sleeping through” means six hours straight. Not twelve. Not 8 p.m. to 7 a.m. Six hours.
On that definition, a majority of six-month-olds manage it at least one night in two — which means two things: it is a real, expected milestone, and a significant proportion of children are not there, and those children are perfectly fine.
A baby who sleeps from 8 p.m. to 2 a.m. is technically sleeping through. It does not make their parents’ lives much easier, and that is exactly the problem with the phrase.
Before three months, the question does not arise
A newborn has a tiny stomach and no internal clock. They wake every two to four hours because they are hungry, and in the first weeks you sometimes have to wake them.
Trying to get a six-week-old to sleep through is not just doomed: it is not desirable. The question becomes relevant at four to six months, not before.
The three most common causes after six months
How they fall asleep in the evening. This is the first by a distance, and the most underestimated. Whatever your baby has at the precise moment they tip into sleep, they will look for at every cycle end. They do about twelve cycles a night. Fall asleep at the breast, and they will ask for the breast several times; fall asleep in the cot, and they will settle back there.
It is not a bad habit to be corrected. It is mechanics.
The end of each cycle: the moment they call you
1 h au total, à partir de l'endormissement
- Sommeil léger
- Sommeil profond
- Sommeil paradoxal
A bedtime that is too late. Counter-intuitive and very common. A baby who falls asleep in sleep debt has more fragmented nights and wakes earlier. Bringing bedtime forward by thirty minutes for a week fixes a good part of end-of-night waking.
Not enough daytime sleep. Same mechanism. Dropping a nap “so they sleep better at night” almost always produces the opposite before twelve months.
What does not fall under those three
Being honest: not everything is a matter of habits.
Reflux, a cow’s milk protein allergy, a lingering ear infection, a sleep-related breathing disorder — loud regular snoring, breathing pauses, very restless sleep with sweating — are real medical causes, and no settling method will fix them. If the wakings come with any of those signs, or with weight gain stalling, that is a consultation, not a blog article.
Major motor milestones, separation anxiety around eight months, teething and changes of childcare also disrupt nights. Those pass on their own, in a few days to a few weeks.
The number to track is not the one you would expect
Do not count the wakings. Count how long it takes them to settle back.
A baby who wakes four times and goes back to sleep in two minutes is doing better than one who wakes twice and takes forty-five minutes. That duration moves first when things improve — and it is the one that actually changes your night.
And if you decide it is not a problem
There are families where the 3 a.m. waking bothers nobody, where co-sleeping is a deliberate choice, where everyone gets enough sleep. In those families there is nothing to fix.
“Sleeping through” has become a grade to achieve, and that is absurd. The only question that matters: are you, today, sleeping enough to cope? If yes, set your mother-in-law’s question aside. If no, there are levers — and they almost always start at the 8 p.m. bedtime, not the 3 a.m. waking.
Frequently asked questions
At what age does a baby sleep through the night?
On the definition used in research — six hours straight — a majority manage it around six months, at least one night in two. A significant proportion are not there at that age and are perfectly fine. Before three months it is not physiologically expected.
My one-year-old still does not sleep through — is that abnormal?
It is not rare, and in itself it is not a sign of a medical problem. It is still worth raising with your GP, partly to rule out reflux, an allergy or a sleep-related breathing disorder, and to look at how the evening bedtime goes.
Should I give a bottle at night so they sleep better?
After six months the nutritional need at night has usually gone, but every child is different and it is a question for your GP, especially if weight is being monitored. What is certain is that a bottle given at every waking quickly becomes a condition for settling back.
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